JPS6136498B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for aralkylating benzene or alkylbenzenes (hereinafter collectively referred to as alkylbenzenes). More specifically, when adding olefins or a mixture thereof to alkylbenzenes, aromatic olefins having a double bond at the position conjugated with the benzene ring (hereinafter collectively referred to as styrenes) are selectively added to aralkyl benzenes. Concerning the method of addition. The addition of various olefins to alkylbenzenes is a Friedel-Crafts reaction.
It is widely known as an important reaction in the chemical industry. This addition reaction is distinguished from the reaction between alkylbenzenes and aliphatic double bond compounds (hereinafter referred to as aliphatic olefins) as an alkylation reaction, and the reaction between styrenes and alkylbenzenes as an aralkylation reaction.
Note that olefins include aliphatic olefins (including so-called diolefins) and aromatic olefins (including styrenes). These terms will be used in the following description. Alkylated products are used as starting materials in the chemical industry and themselves as insulating oils or lubricating oils. On the other hand, aralkylated products have excellent heat resistance, compatibility, and electrical properties, and are industrially preferred aromatic synthetic oils as synthetic oils suitable for heat carriers, plasticizers, reaction solvents, insulating oils, and the like. However, due to difficulties in the manufacturing process, there are not many examples in the chemical industry where this aralkylated product is manufactured alone. The basic chemical structure of the aralkylated product produced by the method of the present invention has a diphenylmethane skeleton in which two benzene rings are bonded to the same carbon atom. Therefore, unlike alkylnaphthalene, alkyl biphenyl, etc., which have been conventionally known as high-boiling aromatic synthetic oils, it is a non-condensed polycyclic aromatic synthetic oil. Methods for obtaining aralkylated products include a method of aralkylating using a halogenated alkylbenzene substituted with halogen at the α position in the presence of a metal halide catalyst such as aluminum chloride, and a method of aralkylating styrene in the presence of an acid catalyst. There are known methods to do this. Treatment of by-product hydrogen halide,
Considering the availability of aralkylating agents, the latter method of aralkylation using styrenes with an acid catalyst is preferred. Conventionally disclosed aralkylation methods using styrenes include a method using a sulfuric acid catalyst as shown in British Patent No. 977322, and a method using a sulfuric acid catalyst as shown in British Patent No.
There is a method using an acidic solid catalyst as shown in No. 896864. However, the present inventors have confirmed that the addition reaction proceeds not only with styrenes but also with aliphatic olefins in the above method. As long as conventional methods are used, there is no selectivity for styrenes or aliphatic olefins, so if a mixture of unsaturated fractions is used as a raw material, a mixture of aralkylated products and alkylated products can be obtained. Only. In order to obtain an aralkylated product alone, it is necessary to use previously isolated styrenes as a raw material, and this method is not industrially advantageous because it uses expensive styrenes. As a result of research on aralkylation reactions, the present inventors discovered a catalyst that selectively causes an aralkylation reaction and completed the present invention. We discovered a catalyst that shows no activity for the alkylation of aliphatic olefins, but only for the aralkylation of styrenes, and created a diphenylmethane structure using a mixture of multi-component unsaturated hydrocarbons as a starting material. This is a completed aralkylation method that produces only non-fused polycyclic aromatics. That is, the present invention provides a step of adding an olefin to at least one kind _of benzene or alkylbenzene whose total number of carbon atoms contained in the alkyl group is ₁ or more and 18 or less. n=1 to 5, m=0 or 1) as a catalyst, the aromatic olefin having a double bond conjugated with a benzene ring is converted into an aralkyl compound at a reaction temperature of 5 to 150°C. The present invention relates to a method for aralkylating benzene or alkylbenzene, which is characterized by carrying out chemical addition. According to the method of the present invention, an aralkylated product having excellent practical properties and suitable for use as a heat medium, plasticity, various solvents, and insulating oil can be obtained by using a crude distillate that is a mixture of aliphatic olefins and styrenes. As a starting material, it can be produced selectively. Next, the present invention will be explained in more detail. The aralkylation catalyst used in the process of the invention is a fluoroalkylsulfonic acid represented by CnF _2o+1-n ClmSO ₃ H. Here, n is an integer of 1 to 5, and m is 0 or 1. In this sulfonic acid, all the hydrogen atoms of the alkyl group are substituted with chlorine or fluorine atoms, and hydrogen ions can be easily dissociated due to the electron donating property of chlorine or fluorine. For this reason, it is extremely strong as an acid, and is a type of strong acid called a super acid (SUPER ACID) because it has an acid strength exceeding 100% sulfuric acid (GAOlah, "Friedel-Crafts Chemistry",
P367, John Wiley & Sons (1973)). The alkylbenzenes used in the method of the present invention are alkylbenzenes in which the total number of carbon atoms in benzene or alkyl groups is 1 or more and 18 or less. In the case of an alkylbenzene in which the alkyl group has 19 or more carbon atoms, elimination and isomerization of the alkyl group occur and the aralkylated alkylbenzene, which is the object of the present invention, cannot be obtained in good yield, which is not preferable. Alkyl groups include straight chain types, branched types, and cyclic side chain alkyl groups such as indane and tetralin. Although not limiting the present invention, specific examples of alkylbenzenes include benzene, toluene, o-,
m-, p-xylene, ethylbenzene 1, 2, 3
-, 1, 2, 4-, 1, 3, 5-trimethylbenzene, o-, m-, p-ethyltoluene, propylbenzene, lower alkylbenzenes such as kyumene, and higher alkylbenzenes whose alkyl group has 4 to 18 carbon atoms. Besides, indane, cyclic alkylbenzene having a tetralin structure, etc. can be mentioned. These alkylbenzenes may be used alone or in a mixture of two or more types when carrying out the present invention. Further, the present invention can be practiced even with a fraction containing aliphatic hydrocarbons as long as the fraction contains the above-mentioned alkylbenzenes. Among the olefins that are one of the starting materials used in the present invention, the aralkylatable component of the present invention is a compound (styrene) having a double bond at a position conjugated with a benzene ring. Specific examples of these include styrene, α-methylstyrene, β-
Examples include alkyl-substituted styrenes such as methylstyrene and vinyltoluene, diolefins such as divinylbenzene, and cyclic styrenes such as indene and alkylindene. These styrenes are
The method of the present invention can be carried out either alone or in a mixture of two or more. Furthermore, as a raw material that can be preferably used in the method of the present invention, aromatic by-product oil (with a boiling point range of 65 to 198 °C) that is produced when petroleum hydrocarbons are thermally decomposed at a temperature of 700 °C or higher mainly for the purpose of producing ethylene ( (hereinafter referred to as aromatic by-product oil).
The composition of the aromatic byproduct oil varies depending on the type of feedstock oil supplied to the cracker and the cracking reaction conditions, but it contains 5 to 15% by weight of saturated aliphatic hydrocarbons and aromatic compounds such as alkylbenzenes. 35～
85 weight percent, 2 to 10 weight percent aliphatic olefins, and 5 to 10 carbon atoms varying from 2 to 15 weight percent styrenes. The fraction, which is a by-product oil of thermal decomposition and has a boiling point exceeding 198°C, contains condensed polycyclic aromatics such as naphthalene, and is not preferred. An analysis example of aromatic by-product oil is shown in Table 1 (composition of aromatic by-product oil).

【table】

[Table] Notwithstanding the above aspects of the present invention, carrying out the method of the present invention using separately isolated styrenes free of aliphatic olefins, such as styrene and/or α-methylstyrene, It should naturally be understood that the present invention is being implemented. In the method of the present invention, the amount of the catalyst to be used can be appropriately selected as long as it is 0.01 mol percent or more based on the alkylbenzene which is one of the reaction raw materials. Although increasing the catalyst concentration does not change the selectivity of aralkylation in the method of the present invention, it is practically necessary to shorten the time to completion of the reaction and conduct the reaction efficiently.
More preferably 0.1 mole percent or more. The reaction temperature is preferably in the range of 5°C or higher and 150°C or lower. If it is less than 5°C, styrenes will polymerize and the yield of the desired aralkylated product will decrease, which is not preferable.
On the other hand, at temperatures exceeding 150°C, thermal polymerization of styrenes becomes significant, leading to increased loss of styrenes and a decrease in the yield of the desired product due to dealkylation and isomerization of alkylbenzenes. In the method of the present invention, the reaction temperature can be appropriately selected as long as the temperature is 5° C. or more and 150° C. or less, but the alkylbenzenes and styrenes must be kept in a liquid phase. The pressure to be applied naturally changes depending on the type of alkylbenzenes and styrenes to be subjected to the reaction, and can be appropriately selected as long as the pressure range is sufficient to maintain the liquid phase of the raw materials. A pressure of 50 Kg/cm ² G or less is usually sufficient. The desired products of the method of the present invention are a 1:1 adduct in which one molecule of styrene is added to one molecule of alkylbenzene, and a 1:2 adduct in which two molecules of styrene are added to one molecule of alkylbenzene.
Next, a 1:1 adduct and a 1:2 adduct will be explained using xylene and styrene as starting materials as an example. The 1:1 adduct is monostyrenated xylene (1-xylyl-1-phenylethane), but when mixed xylene is used as a raw material, a mixture of four isomers is used depending on the four constituent isomers. could be. This 1:1 adduct was determined to have a molecular weight of 210 by mass spectrometry (hereinafter referred to as m/e value).
It is a liquid with a normal pressure boiling point of 292-305°C. The 1:2 adduct is a compound in which 2 moles of styrene is added to xylene, and has a single peak with an m/e value of 314. However, when mixed xylene is used as a raw material, depending on the four constituent isomers, or It is a mixture of various isomers depending on the position of styrene added. This 1:2 adduct has a boiling point of 180 DEG -240 DEG C. under reduced pressure of 3 mm Hg. Furthermore, the heavier products are styrene polymers, which are undesirable products, and their formation must be avoided. The reaction molar ratio of the present invention, that is, the molar ratio of alkylbenzenes to styrenes, is at most 1:2, and the amount of styrene used can be selected as appropriate. The production ratio of the desired product in this range is 1:1 adduct: 1:2
The adduct can be varied within the range of 1:0.91 to 1:0.01. If the molar ratio exceeds 1:2 and excessive use of styrene is used, the conversion rate of styrene to the desired product will decrease, which is not preferable. Example 1 The present invention will be explained more specifically by showing examples and comparative examples. Example 1 10 g of o-xylene and 0.05 g of trifluoromethanesulfonic acid as a catalyst were placed in a test tube with a capacity of 50 ml, and the mixture was placed in a hot water bath at a temperature of 50°C. While stirring, 3 g of an equal weight mixture of styrene and octene-1 is added dropwise. After completing the dropwise addition, neutralize, wash with water, and reduce the temperature to 3 mm of mercury column.
Heat to 95°C to remove light fractions. The remaining liquid product has a peak with m/e value of 210 and is a 1:1 adduct of o-xylene and styrene. Octene-1 was not reacted since no peak with an m/e value of 218 corresponding to the addition product of octene-1 and xylene was observed. Example 2 In this example, in order to confirm the selectivity of alkylation and aralkylation, the following alkylbenzenes and olefins were reacted in combination in the same manner as in Example 1. Confirmation after reaction is m/
I did it using the e value. Eight types of alkylbenzenes were used: benzene, toluene, o-xylene, pseudokyumene, t-butylbenzene, t-amylbenzene, n-octylbenzene, and n-dodecylbenzene. Aliphatic olefins include octene-1, octene-2, 2-ethylhexene-1, 2, 4,
4-trimethylpentene-1, 2,4,4-trimethylpentene-2, 1,3-cyclooctadiene, 1,5-cyclooctadiene, 1,7-octadiene, cyclooctene, 2,5-dimethyl-
Twelve types of 2,4-hexadiene, 2,4-dimethylcyclohexene, and ethylidenecyclohexane were used. Five types of styrene were used: styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, and indene, and arylbenzene was used as the unconjugated aromatic olefin. The results are summarized in Table 2. In the same table, ○ marks indicate those that were confirmed by m/e value, and × marks indicate those that could not be confirmed by m/e value.

【table】

[Table] As is clear from Table 2, the selectivity between aliphatic olefins and styrenes is very good regardless of the type of alkylbenzene.
It is also found that arylbenzene, which is an aromatic olefin, has no conjugated position between the double bond and the benzene ring and is inactive. Example 3 780 g of benzene and 10 g of trifluoromethanesulfonic acid as a catalyst were placed in a reactor and heated and stirred to bring the temperature to 60.
Keep at ℃. Aliphatic olefin mixture containing propylene tetramer as the main component (boiling point range 185-210
℃, average molecular weight 170) and 118 g of vinyltoluene mixture (m:p weight ratio 65:35) were mixed,
The mixture was added dropwise to the reactor while maintaining the reaction temperature at 60±2°C.
After the dropwise addition is completed, the catalyst is separated and neutralized and washed with water. 860g of light fraction with distillation temperature up to 220℃ is recovered by atmospheric distillation, and then distilled under reduced pressure of 3mmHg with distillation temperature of 130~155℃.
170 g of a first fraction having a temperature of 190 to 220°C, 22 g of a second fraction having a temperature of 190 to 220°C, and 9 g of a distillation residue were obtained. m/ of the first fraction
The e value is a single peak of 196, which is a 1:1 adduct of benzene and vinyltoluene, and the m/
The e-value is a single peak of 314, which is a 1:2 adduct of benzene and vinyltoluene. Both the first and second fractions are adducts of propylene tetramer m/e
No peaks with values of 246 (dodecylbenzene) and 414 (didodecylbenzene) were observed, confirming good selectivity between aliphatic olefins and aromatic olefins. Example 4 A reaction was carried out using the aromatic by-product oil having the composition shown in Table 1, which was explained as an analysis example of aromatic by-product oil. Heat and stir 100 g of toluene and 10 g of trifluoromethanesulfonic acid and maintain the temperature at 40°C. Keep 1000g of aromatic by-product oil at a temperature of 40±5℃,
Add dropwise over 3 hours. After finishing the dropwise addition, maintain the temperature at 40℃.
Continue stirring for 30 minutes to complete the reaction, and perform catalyst separation and neutralization washing. Light distillate 960 with distillation temperature up to 225℃
g was recovered by atmospheric distillation. Under reduced pressure of 3 mmHg, 110 g of a first fraction with a distillation temperature of 135-170°C and 25 g of a second fraction with a distillation temperature of 190-240°C were obtained. The first fraction has m/e values of 182, 196, 210, 224,
It is a mixture showing a distribution of 238 and 242, both of which are diphenylmethane type compounds (CnH ₂ n- ₁₄ ). Second
The fractions are a mixture showing a distribution of m/e values of 286, 300, 314, and 328, all of which are triphenyl type compounds (CnH ₂ n- ₂₂ ). As a result, no product of CnH ₂ n- ₆ , which is an adduct of aliphatic olefins, was observed. Examples 5 to 7 530g of m-xylene and a predetermined amount of trifluoromethanesulfonic acid as a catalyst were charged into a reactor,
Keep the temperature at 130℃ while stirring, keep the temperature at 130±5℃
104g of styrene was added dropwise over an hour.
After completing the dropwise addition, wash with neutralized water. By distillation, 3mm
A fraction with a distillation temperature of 125-140°C is obtained under reduced pressure of Hg.
This fraction has a single peak with an m/e value of 210 and is a 1:1 adduct of styrene and m-xylene. The results are shown in Table 3.

[Table] Here, the styrene yield is a numerical value expressed in mole percent of the proportion of styrene converted into the desired 1:1 adduct with respect to the styrene subjected to the reaction. Examples 8 and 9 740 gr of t-amylbenzene and 5 g of trifluoromethanesulfonic acid are charged into a reactor, and 104 gr of styrene is added dropwise over 1 hour at a predetermined temperature. After neutralization and washing with water, the distillation temperature is reduced to 3 mmHg by distillation.
A fraction of 135-165°C was obtained. This fraction has m/e value
252, a 1:1 adduct of t-amylbenzene and styrene. The results are summarized in Table 4.

[Table] Examples 10 to 14 1060 g of o-xylene and 15 g of trifluoromethanesulfonic acid as a catalyst were charged into a reactor and the temperature was 60±.
React the required amount of styrene at 5°C. After the reaction is completed, the mixture is neutralized, washed with water, and distilled. A first fraction, a 1:1 adduct, with a distillation temperature of 130-155°C and a second fraction, a 1:2 adduct, with a distillation temperature of 180-230°C were obtained under reduced pressure of 3 mmHg. The results are shown in Table 5.

[Table] In the same table, the styrene yield is a number indicating the mole percent of styrene converted into the first and second fractions, which are the target products, based on the styrene used in the reaction.
In Example 14, the molar ratio of o-xylene to styrene was 1:
2,2, and it was observed that as the molar ratio of styrene to xylene increased, the styrene yield tended to decrease. Example 15 The same procedure as in Example 1 was carried out using pseudokymene as the alkylbenzene, α-methylstyrene as the styrene, and octene-1 as the aliphatic olefin. However, the catalyst concentration is 0.1 to 0.1 molar percent relative to pseudokymene.
Adjust to be within the range of 0.05. The catalyst used was
C ₂ F ₅ SO ₃ H, C ₃ F ₇ SO ₃ H, C ₄ F ₉ SO ₃ H,
m/e value of 5 types of C ₅ F ₁₁ SO ₃ H and CClF ₂ SO ₃ H, all of which are adducts of α-methylstyrene.
238, but no formation of octene-1 adduct was observed. Comparative Example 1 The same procedure as in Example 3 was carried out using 97% sulfuric acid as a catalyst to obtain 315 g of a fraction having the same distillation temperature as the first fraction of Example 3. Based on the m/e value, this fraction contains 210, which is an adduct of benzene and vinyltoluene, as well as 204, 218, 232, 246, 260, 274, and 288, and CnH ₂ n-, which is an alkylated product of aliphatic olefins. It was confirmed that it contained type 6 compound. Example 16 All examples were Example 5 except that the amount of catalyst used was 0.07g.
I did the same thing. At this time, the amount of catalyst used relative to m-xylene was 0.009 mol%. The yield of the fraction was 115 g (styrene yield 55%). The m/e value of this fraction is 210 and contains 208 components. The m/e value of 208 was a styrene dimer produced by dimerizing styrene without aralkylation. Comparative Examples 2 and 3 The same procedure as in Example 8 was carried out except that the reaction temperature was changed. The results are shown in Table 6.

[Table] In addition to the m/e value of 252, the fraction of Comparative Example 2 contains a component having an m/e value of 208, which is a styrene dimer. In addition, the m/e value of the fraction of Comparative Example 3 confirmed that in addition to the target product 252, it contained components 192 and 312, which are products of elimination and disproportionation of the t-amyl group. It was done. Comparative Example 4 Nonadecylbenzene as alkylbenzene
34.5g and catalyst trifluoromethanesulfonic acid
Add 2.1 g of styrene dropwise to 0.1 g while stirring while maintaining the temperature at 130±5°C. After completion of the dropwise addition, the reaction mixture was washed with neutralized water and subjected to mass spectrometry. The m/e value of nonadecylbenzene itself is not a single peak of 344 but 344±14×
It showed a peak of n (n is an integer), and it was confirmed that disproportionation, isomerization, and elimination of the alkyl group had occurred.

Claims (1)

[Claims] 1. In the step of adding an olefin to benzene or at least one alkylbenzene whose total number of carbon atoms contained in the alkyl group is 1 or more and 18 or less, the general formula CnF _2o+1-n ClmSO ₃ An aromatic olefin having a double bond that is conjugated with a benzene ring at a reaction temperature of 5 to 150°C by the presence of at least one compound represented by H (n = 1 to 5, m = 0 or 1) as a catalyst. 1. A method for aralkylating benzene or alkylbenzene, which comprises adding aralkylated benzene or alkylbenzene. 2. Claim No. 2, wherein the benzene or alkylbenzene and olefins are a fraction with a boiling point range of 45 to 198 °C among thermal decomposition by-product oils obtained when petroleum hydrocarbons are thermally decomposed at 700 °C or higher. 1
Aralkylation method described in section. 3. The aralkylation method according to claim 1 or 2, wherein the olefins include both an aliphatic olefin and an aromatic olefin having a double bond conjugated with a benzene ring.